Techniques for transmitting mobile communication signals through vehicle windshields have been adopted in the recent past. This is particularly true with the advent of cellular telephones for use in mobile communications. Two prior art U.S. patents relating to through-the-glass coupling form mobile communications systems are Kirkendall U.S. Pat. No. 4,089,817 and Blaese U.S. Pat. No. 4,658,259. In each of these systems, an elongated antenna is mounted to a windshield or other non-conducting vehicle portion and signals are sent and received through the motor vehicle windshield using impedance matching techniques disclosed in those prior art patents.
U.S. Pat. No. 4,474,353 Martino et al. discloses a technique for mounting an elongated antenna to a windshield. In accordance with the disclosure of this patent, a piece of double sided tape is used to hold an antenna base in place and the engagement between the double sided tape and the windshield is protected by a silicone material which shields the double sided tape from contact with moisture which otherwise would degrade the adhesion.
The use of the double sided tape in the aforementioned patent reduces the incidence of cracking of the windshield due to different coefficients of expansion of cements used in the prior art for gluing the antenna mount to the windshield. While avoiding the windshield cracking problem, the use of the double sided tape required application of a silicone protective layer around the outer perimeter of the tape to avoid degradation of the adhesion as moisture contacted the double sided tape. The resultant antenna mounting technique disclosed in the '353 patent is a multiple step process involving overlying portions of the mount and application of silicone around the outer periphery of the mount to avoid weakening of the adhesion.